Referring to FIG. 6, a typical example of conventional electronic components mounting apparatus will be explained. In FIG. 6, an orthogonal robot 31 moves a mounting head 32 to an arbitrary position in x and y directions. On the tip of the mounting head 32 is provided a suction nozzle 33 which can be moved up and down. A chuck may be used in place of the suction nozzle 33.
A circuit board holder 34 holds at a predetermined position an electronic circuit board 35 supplied from outside the apparatus. An electronic components holding unit 36 stores electronic components to be mounted on the electronic circuit board 35. On the electronic components holding unit 36, a plurality of electronic component supplying cassettes 37 is arranged in a line.
In the above construction, when an electronic component is to be mounted, the mounting head 32 first moves to the electronic components holding unit 36, picks up an electronic component from an preferable electronic component supplying cassette 37 on the electronic components holding unit 36 by means of the suction nozzle 33; subsequently the mounting head 32 moves to the circuit board holder 34 and mounts the electronic component at a predetermined position on the pre-positioned electronic circuit board 35.
In the above described conventional electronic components mounting apparatus, as the number of types of electronic components to be mounted on the electronic circuit board 35 increases the number of the electronic component supplying cassettes 37 to be arranged on the electronic components holding unit increases making it necessary to either install more than one unit of electronic components mounting apparatus or a larger-capacity electronic components mounting apparatus.
In the meantime, there exist different types of electronic components such as chip resistors which are the same in construction, configuration, and dimensions yet have different characteristic values. In the conventional method, it has been necessary to cope with such situation by arranging on the electronic components holding unit 36 an electronic component supplying cassette 37 for each of the component types. It was thus sometimes necessary to install more than one main units or a larger-size main unit of the mounting apparatus resulting in increase in equipment cost and the management cost of electronic component supplying cassettes.